Filament support



' Nov. 8, 1932. VAN HORNE 1,886,991

FILAMENT SUPPORT Filed March 29, 1926 W bm%w filil W fitter nut PatentedNov. 8, 1932 I V STATES PATENT OFFICE ,J'OHN' s. VAN HORNE, or FRANKLIN,OHIO, ASSIGNOR 'ro RADIO CORPORATION or AMERICA, A coRPonArro voPDELAWARE FILAQMEN'I SUPPORT Application fil ed March 29, nae.v SerialNo. 98,166.

' My invention relates to electron discharge tension "against the edgesof the interposed 'devic'es embodying filamentary electrodes and 'micabridge to dampen the vibration. lVhile more particularly to thermionicvalves or other materials may be employed, and other radio tubes, thepurpose being to eliminate means of supporting the filament or holdingmicrophonic noises by minimizing the vibrait against vibration may beutilized, the mica tion-ofthe electrode filament. bridge is preferred,since it not only aifords While the microphonic noises reproduced a highdielectric resistance, but is also low in the head phones or loudspeaker units of in heat conductivity, and therefor will have aradiorecelving set may to some extent be a minimum cooling effect, uponthefilament induced by other elements of a thermionic causing minimumdissipation and thereby but Valve or radio tube, it has been found bySlightly, if at all, affecting the emission of experiment and researchthat such noises are electrons. p 5 caused primarily by vibrations ofthe heated With the above primary and other incifilament or electronemitting element, which dental objects in View as will more fully 15 bcau of it fragile at re is suallymor appear in the specification, theinvention co nor 'less flexibly or loosely mounted and is sists of thefeatures of construction, the parts -highly susceptible tovibratorymotion. The and combinations thereof, and the mode of hum or ringingsound'produced by such vibra- Operation or their equivalents ashereinafter tion is greatly magnified and augmented by described and setforth in the claims.

20 the radio receiving apparatus and is finally Referring to theaccompanying drawing, reproduced as a harsh discordant and dis- Fig. 1is a perspective view of an, assembled gr abl oi I r I thermionic valveor radio tube, with oneside I In the present invention, the eliminationof the anode or plate elementremoved, Fig.2 or at least, the minimizingof such obj ection- [Is an enlarged vertical sectional View at right 25able noises Y is contemplated by supporting angles to the plane of viewof Fig. 1. Figs. 3, the electrode filament at one or more inter- 4 and 5illustrate different methods of supmediat'e points, thereby dampeningthe viporting or dampening electrode filaments of bration of thefilament or dividing the filathe hair-pin type. Figs. 6, 7 and 8illustrate ment into two or more sections of reduced furthermodifications, more particularly as 30 length, which will not respond tovibration, pplied to single strand filaments.

or if vibration should occur, it will be at Like parts are indicated bysimilar characsuch rate as to be inaudible. As a conventers of referencethroughout the several ient andeconomical embodiment of the inviews.vention for commercial producti0n,it is pr'e- In the preferred form ofembodiment illusferred to provide a support or bridge of thin trated inthe drawing, 1 is, the bulb or mica, which engages with the filament ata envelope of a thermionic valve of which 2 mid-length point. In theusual and popular is the press or stem, supporting the several assemblyof thermionic valves or radio tubes, elements. Connected with conductors3 into wherein is employed an electrode filament of the press 2, is anelectron emitting electrode the hair-pin type surrounded by a grid ele-0r filament 4, of inverted V shape or hair-pin ment on opposite sides ofwhich'extend the type, the bight of which is supported by anplate oranode elements, it is preferred to anchor arm 5 also supported by thepress 2. interpose such dampening bridge of mica or Surroundingtheelectron emitting element 4 the like, intermediate the reverse strandsof is a helical winding 6 of fine wire supported the hair-pin filament,and extending in transupon upright fingers or standards 7 and verserelation through the grid element and forming the grid element.Enclosingthe abutting upon the plate or anode element grid and filamentis an anode or plate element on opposite si'desthereof. The mica bridge8, usually formed in two interconnecting or support is of such size asto slightly spread plates, extending on opposite sides the grid I 50 thestrands of the filament causing suflicient element, and supported uponarms 9, one of which is continuous through the press 2, for electricalconnection of the plate into an electrical circuit, as is also one ofthe supporting fingers or standards 7 of the grid element. The anchorarm 5 of the electron emitting filament 41 is quite fine and flexible inorder to yieldingly support the filament against breakage by shock andalso to accommodate expansion and contraction of the filament. Thisflexible mounting necessary for the preservation of the fragile filamentis more or less directly responsible for the noise inducing vibration.

To minimize the vibration of the filament without subjecting thefilament to undue tension, a spreader 10 of preferably electrically andalso thermally insulating material is interposed between, the strands offilament 4. This bridge or spreader 10 is preferably a smallrectangularvpiece of thin mica. The spreader 10 extends transverselythrough the grid element, intermediate successive turns or convolutionsof the grid wire 6, and is of such length as to abut upon the innerfaces of the plate or anode element 8 at the opposite ends. The width ofthe spreader or bridge 10 is suficient that the filament strand willrest against the edges of the bridge or support, with only such pressureto arrest their vibration. The portions of the strand at opposite sidesof'the bridge or support are usually thrown slightly out of alignment orare very slightly angular one to the other. This bridge or support 10 isquite thin and very light and easily supported in its adjusted position,in which it is held against lateral movement in one direction, by itsterminal abutment upon the inner faces of the plate element 8, andagainst movement transversely by its engagement with the filament strand4:. It is supported vertically by the helically wound wire 6 of the gridelement. Being thus disposed it braces the filament 4 against unduevibration and if any vibrations occur, it is in the shortened length offilament above and below the bridge or support, the rate of vibration ofwhich is such as to be inaudible if it does occur, the length of suchsections being so short as to be normally unresponsive to vibratorytendencies. The bridge or support is located at approximately themid-length point of the filament strand, although it need not be exactlyso located. If so located as to divide the filament strand into unequalsections, they will not only produce a high vibratory rate, if vibrationshould be in duced, but being unequal, they will possess differentvibratory rates, and tend to neutralize each other. In the case ofextremely long filaments or strands, two or more rests or supports 10'"may be provided as shown in Fig. 6. In any event, the filament isrestricted to a succession of comparatively short sections or lengths,which are not readily susceptible to vibration, but in which ifvibration should be induced, it would occur in such frequency as to beinaudible.

Various methods of supporting the filament to arrest or minimizevibration may be employed. In Fig. 3, the support or rest has been shownprovided with spaced holes 11, through which the filament strands aextend. In Fig. 4, the rest or bridge is shown provided with marginalnotches 12, in which the filament strands engage. In Fig. 5 there isshown a modified construction, where in lieu of a spreader or bridgemember interposed between the strands of the electrodes, eachfilamentstrand is separately supported by a tie 13 of insulatingmaterial medially connecting the filament strand with the spacedstandards or supporting fingers 6 of the grid element. Figs. 6 and 7show the damping support applied to a single strand filament, which mayeither bear against the marginal edge ofsuch support or rest as shown inFig. 6, or may pass through a central orifice therein, as shown in Fig.7. In Fig. 8, the damping support is shown applied to a radio tube andthe like, employing a radially disposed anode and monulating plates,arranged about the central filament 42 In this case, the damping supportor rest- 10, is preferably provided with marginal notches, which engagethe radially disposed element plates 1a and is further provided with acentral orifice through which the filament strand extends. I

Fromthe above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modification in its form, proportions,detail construction and arrangement of parts without departing from theprinciple involved or sacrificing any of its advantages.

While in order to comply with the statute, the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificdetails shown, but that the means and construction herein disclosedcomprises the preferred form of several modes of putting the inventioninto effect, and the invention is, therefore, claimed in any of itsforms or modifications within the legitimate and valid scope of theappended claims.

Having thus described my invention, I claim:

1. In a thermionic valve, the combinatio with a filament, a grid elementsurrounding the filament, and a plate element extending on oppositesides of the grid element, of an auxiliary support for the filament withwhich the filament engages at amidlength point.

said support extending transversely through the grid element andabutting upon the element at opposite sides of the grid element. thefilament plane.

' In testimony whereof, I have hereunto set my hand this l9ida' of MarchA. D. 1926.

2. A thermionic valve, wherein a hairpin type of electrode filament issurrounded by a grid element, and a plate element which extends 011opposite sides of the grid element,

characterized by a brace of dielectric material interposed between thestrands of the hairpin electrode and extending transversely through thegrid element into abutment with the plate element on opposite sidesthereof.,

3. Means for minimizing microphonic noises of thermionic valves and thelike, 1n-

cluding the combination with an electrode filament, an anode and a gridelement symmetrically disposed about the plane of said filament of adampening element engaging the electrode filament of such valve atamidlength point and deflecting the filament in said plane and out ofaligned direction to eliminate vibration.

4. In a thermionic valve, the combination with a. hairpin typeofelectrode filament having its strands included in a plane, of a spreadedmember interposed between and distending the strands but in said sameplane whereby microphonio noises due to'filament Vibration is materiallyreduced. I I

5. Means for supporting a substantially V-type filament of a thermionicvalve, comprising a spreader member interposed be-' tween the spacedstrands of the filament intermediate its bight and ends, the spreaderbeing of greater extent than the normal spacing of the filamentstrandsat the points of engagement, whereby the strands are deflected intheir normal'plane and out of normal alignment bytheir engagement withthe spreader. v

6. The combination with a substantially Y V-sha-ped filament for athermionic valve, of a spreader interposed between the arms of theV-shaped filament at an intermediate point and deflecting the arms ofthe filament out of straight lines in contrary directions I but in theirnormal plane.

7 The combination with a substantially V-shaped filament for athermionic valve, of a perforated brace member for the filament, throughthe perforations of which the arms of the V-shaped filament extend, thestrandreceiving perforations being diiferently spaced from thenormalspacingof the arms at their points of engagement with the bracemember, whereby the arms are deflected out of straight lines.

8. In a thermionic tube, the combination with an inverted normallyV-shaped filament having its legs lying in a common plane, of aninsulating member interposed between the filament legs in straddledfashion and causing them to be outwardly extended but in the same plane,said insulatingmember ly- JO N S. VAN HORNE.

plate ing in a plane substantially perpendicular to CERTIFICATE OFCORRECTION.

Patent No. 1,886,991. November 8, 1932.

JOHN S. VAN HORNE.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 3,line 26, claim 4, for "spreaded" read "spreader", and iine 27, after"strands"insert the words "out of aligned direction";and that the saidLetters Patent should be read with these corrections therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of May, A. D. 1933.

M. J. Moore.

(Seal) Acting Commissioner of Patents.

